For the first time, a comparative analysis of the limb axis in patients with unilateral knee OA will be conducted compared to the contralateral uninjured side using Multisliced computed tomography (MSCT) and vertical CT (weight-bearing CT). This analysis will identify the pathological and physiological degrees of varus in patients with unilateral gonarthrosis. Indications for mechanical and kinematic limb axis alignment will be substantiated depending on the degree of varus deformity. Aim of the study: To improve the results of total knee arthroplasty in patients with varus deformity by optimizing the degree of varus correction. Objectives: To analyze physiological and pathological varus in patients with unilateral osteoarthritis under physiological loading. To develop an algorithm for applying various types of limb alignment.

Inclusion Criteria:

1. Patients over 18 years of age with grade 3-4 knee osteoarthritis (according to Kellgren-Lawrence) and pain score of 5 or higher on a 10-point VAS scale.
2. Varus deformity of the lower limb (HKA angle <177°, or varus >3°)
3. Anesthesia risk according to the ASA scale of no more than III.
4. BMI less than 35 kg/m2.
5. Patient must be monitored throughout the entire study period (12 months).
6. Patient must be mentally competent and compliant.
7. Patient must provide written informed consent to participate in the study.

Exclusion Criteria:

1. Body mass index > 40 kg/m².
2. Instability of the collateral ligaments of the knee joint requiring the installation of ligamentous systems, presence of primary severe bone defects.
3. Impaired weight-bearing ability of the contralateral limb.
4. Presence of metal implants or foreign bodies in the lower extremities.
5. Previous knee interventions, such as reconstruction of the knee ligament apparatus, or corrective osteotomies of the femur and tibia.
6. Patient refusal to participate in the study.
7. Patient failure to comply with the recommendations of the treating physician or the prescribed regimen.